Question

What is the change of energy where the wavelength is 4078 A

Answer 1

The change of energy : 4.8744 x 10⁺¹⁹ J

Further explanation

Radiation energy is absorbed by photons

The energy in one photon can be formulated as

$\large{\boxed{\bold{E\:=\:h\:.\:f}}}$

Where

h = Planck's constant (6,626.10⁻³⁴ Js)

f = Frequency of electromagnetic waves

f = c / λ

c = speed of light

= 3.10⁸

λ = wavelength

The wavelength is 4078 A = 4.078 x 10⁺⁷ m

$\tt E=h.\dfrac{c}{\lambda}\\\\E=6.626\times 10^{-34}\times \dfrac{3.10^8}{4.078\times 10^{-7}}\\\\E=4.8744\times 10^{-19}~J$